@article{COCV_2010__16_3_648_0,
     author = {Freitas, Pedro and Siudeja, Bat{\l}omiej},
     title = {Bounds for the first {Dirichlet} eigenvalue of triangles and quadrilaterals},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {648--676},
     publisher = {EDP-Sciences},
     volume = {16},
     number = {3},
     year = {2010},
     doi = {10.1051/cocv/2009018},
     mrnumber = {2674631},
     zbl = {1205.35174},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/cocv/2009018/}
}